Dissociation of large- p T prompt J / ψ produced in Pb–Pb collisions at the LHC

Abstract A collision of a light meson and a charmonium produces quarks and antiquarks first, then the charm quark fragments into a charmed hadron, and finally three or more mesons are produced. This is the mechanism that we consider and propose to understand the prompt- J / ψ nuclear modification factor in the range of J / ψ transverse momentum from 10 GeV/ c to 18 GeV/ c , as measured by the CMS Collaboration and the ATLAS Collaboration. Unpolarized cross sections are derived and calculated for the reactions π + charmonium → H c + X with H c being D + , D 0 , D s + , D ⁎ + , or D ⁎ 0 . Numerical cross sections are parametrized and used to calculate the dissociation rate of charmonium in the interaction with pions in hadronic matter. The momentum dependence of the rate obtained is so as to lead to a decreasing charmonium nuclear modification factor with increasing transverse momentum.